Flutter Websockets MacOS：相同的代码在调试模式下有效，但在发布模式下无效：(操作系统错误：提供了 node 名或服务名..)

摘要

我有一个使用WebSockets的程序，该程序在debug模式下功能齐全，但在release模式下运行相同的exact代码会导致错误.

语境

Flutter 文档教会我们how to work with WebSockets个.

让我们使用official代码示例来处理WebSockets(我对它进行了一些修改，以在Text小部件中显示错误):

import 'package:flutter/material.dart';
import 'package:web_socket_channel/web_socket_channel.dart';

void main() => runApp(const MyApp());

class MyApp extends StatelessWidget {
  const MyApp({super.key});

  @override
  Widget build(Build语境 context) {
    const title = 'WebSocket Demo';
    return const MaterialApp(
      title: title,
      home: MyHomePage(
        title: title,
      ),
    );
  }
}

class MyHomePage extends StatefulWidget {
  const MyHomePage({
    super.key,
    required this.title,
  });

  final String title;

  @override
  State<MyHomePage> createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  final TextEditingController _controller = TextEditingController();
  final _channel = WebSocketChannel.connect(
    Uri.parse('wss://echo.websocket.events'),
  );

  @override
  Widget build(Build语境 context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),
      ),
      body: Padding(
        padding: const EdgeInsets.all(20.0),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            Form(
              child: TextFormField(
                controller: _controller,
                decoration: const InputDecoration(labelText: 'Send a message'),
              ),
            ),
            const SizedBox(height: 24),
            StreamBuilder(
              stream: _channel.stream,
              builder: (context, snapshot) {
                if (snapshot.hasData) {
                  return Text(snapshot.data.toString());
                } else if (snapshot.hasError) {
                  return Text(snapshot.error.toString());
                } else {
                  return const Text('listening...');
                }
              },
            )
          ],
        ),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: _sendMessage,
        tooltip: 'Send message',
        child: const Icon(Icons.send),
      ), // This trailing comma makes auto-formatting nicer for build methods.
    );
  }

  void _sendMessage() {
    if (_controller.text.isNotEmpty) {
      _channel.sink.add(_controller.text);
    }
  }

  @override
  void dispose() {
    _channel.sink.close();
    _controller.dispose();
    super.dispose();
  }
}

问题

如果在调试模式下在MacOS上运行上述代码片段，它将正常工作.但是，如果您使用flutter build macos构建应用程序，您将收到以下错误:

SocketException: Failed host lookup: ‘...’ (OS Error: nodename nor servname provided, or not known, errno = 8)

我所try 的

1. SocketException: Connection failed (OS Error: Operation not permitted, errno = 1) with flutter app on macOS个 上面说要加上这个 <key>com.apple.security.network.client</key> <true/>

2. SocketException: Failed host lookup: ‘...com’ (OS Error: nodename nor servname provided, or not known, errno = 8)个

3. ssh: Could not resolve hostname [hostname]: nodename nor servname provided, or not known个

4. 关闭了我的防火墙.

5. 已确保有活动的互联网连接.

问题

Why does the above snippet work in Debug mode, but not in release mode when running 100?

Note

正在运行

flutter doctor -v

显示"未发现问题".